The Current Understanding on Langerhans' Cells and Its Role in Oral Lesions

Description of Langerhans' cells (LCs) as an important antigen-presenting cells responsible for detecting the antigens, recruiting T-cells, and thereby initiating the immune response. An adequate response of the mucosal immune system is essential to protect the mucosa against pathological conditions. Hence, a detailed review was planned about this unique antigen-presenting cell.

A literature search of the electronic databases included the MEDLINE, EBSCOHOST, PUBMED, and hand searches of references retrieved were undertaken using the following MeSH terms "Langerhans cells," "LCs in Oral Lichen Planus," "Langerhans cell histiocytosis," "LCs and HIV," "LCs in Periodontitis."

LCs are present suprabasally in the epithelium of oral mucosa and in the epidermis of the skin. The role played by LCs though not fully elucidated, but several research studies indicate that these cells are involved in the pathogenesis of many oral diseases. In this article, the historical perspective, structure, function, origin, and phenotypic expressions of LCs are discussed in detail. The current understanding on the role of LCs in various oral lesions and its immunological characteristics are discussed.

LCs act as immune mediator cells, tumor cells, vectors of infected cells, and phagocytic cells. Further studies could bolster the knowledge about the role of Langerhans cells in the immune response of various oral diseases and thereby provide diagnostic tools and help for prognostic evaluation. This review illuminates the pivotal role of Langerhans cells and its immune surveillance as a "Sentinels" of the oral mucosa.